Outlook keeps track of time zones and daylight saving time so that events automatically appear at the correct time on your calendar.
For example, imagine that your workplace is in Los Angeles and your colleague's workplace is in New York, which is three hours ahead of Los Angeles. When your colleague sends you an invitation for a conference call at 11:00 A.M. New York time (Eastern Time), Outlook adjusts the meeting time to 8:00 A.M. (Pacific Time) when you view it on your laptop in Los Angeles.
If you change the time zone on your laptop, Outlook updates events on the calendar to the correct time for the new time zone. For example, if you travel to another time zone and, upon arrival you change the laptop's System Preferences to the new time zone. When you open Outlook, all events on the calendar are updated accordingly.
When you create a new event, Outlook uses the default time zone that is set in your Outlook preferences for Calendar. If you want, you can specify a different time zone for an event as you are creating it. To display the Time zone selector in the meeting window, on the Meeting tab, click Time Zone.
For example, if you will be traveling from Los Angeles to New York, you might want to create an event that will occur in New York's time zone instead of your workplace time zone. By specifying the specific time zone of the event, you can make sure that the event time will be accurate, even if you travel and change the time zone on your laptop.
When Outlook receives invitations or imports events from applications that don't store time zone information, Outlook assigns the time zone that is set in your Outlook preferences for Calendar.